Update Interop examples to Ice 3.8

[bernardnormier]

This PR upgrades the two Interop examples to use Ice 3.8. It also replaces a few references to Ice 3.7 by references to Ice 3.8.

[Copilot]

Pull request overview

This PR updates the Slice-based Ice interop examples and related documentation links to align with ZeroC Ice 3.8 (switching the examples to the Ice 3.8 “greeter” demos and refreshing doc URLs).

Changes:

• Replace the old “minimal” interop example with a new InteropGreeter example targeting Ice 3.8 greeter.
• Update InteropIceGrid to use a Greeter Slice contract and the IceGrid greeter demo conventions.
• Refresh various Ice documentation links (including moving an older 3.7 link to the archive domain).

Reviewed changes

Copilot reviewed 20 out of 21 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/IceRpc/ConnectionOptions.cs	Updates a documentation link for Ice ACM heartbeat configuration.
src/IceRpc.RequestContext/README.md	Updates Ice request context documentation link to Ice 3.8.
src/IceRpc.Locator/README.md	Updates Ice locator documentation link to Ice 3.8.
examples/slice/README.md	Updates the examples index: adds InteropGreeter and removes InteropMinimal.
examples/slice/InteropMinimal/slice/Hello.slice	Removes the deprecated InteropMinimal Slice contract.
examples/slice/InteropMinimal/Server/HelloService.cs	Removes the deprecated InteropMinimal server implementation.
examples/slice/InteropMinimal/README.md	Removes the deprecated InteropMinimal documentation.
examples/slice/InteropMinimal/Client/Program.cs	Removes the deprecated InteropMinimal client program.
examples/slice/InteropIceGrid/slice/Hello.slice	Removes the old Hello Slice contract for the IceGrid interop example.
examples/slice/InteropIceGrid/slice/Greeter.slice	Adds the Greeter Slice contract for Ice 3.8 IceGrid greeter demo interop.
examples/slice/InteropIceGrid/README.md	Updates instructions/links to point to Ice 3.8 IceGrid greeter demos.
examples/slice/InteropIceGrid/Client/Program.cs	Updates the client to use Greeter and the IceGrid locator identity conventions.
examples/slice/InteropIceGrid/Client/Client.csproj	Switches Slice input from Hello.slice to Greeter.slice.
examples/slice/InteropGreeter/slice/Greeter.slice	Adds a new Greeter Slice contract for the new interop example.
examples/slice/InteropGreeter/Server/Server.csproj	Adds new InteropGreeter server project wiring for Greeter.slice.
examples/slice/InteropGreeter/Server/Program.cs	Adds an Ice protocol server entrypoint using default ice port.
examples/slice/InteropGreeter/Server/Chatbot.cs	Adds Greeter service implementation with Ice checked-cast support.
examples/slice/InteropGreeter/README.md	Adds documentation for the new Ice 3.8 greeter interop example.
examples/slice/InteropGreeter/InteropGreeter.slnx	Adds a solution file for the new example.
examples/slice/InteropGreeter/Client/Program.cs	Adds an Ice protocol client calling /greeter.
examples/slice/InteropGreeter/Client/Client.csproj	Adds new InteropGreeter client project wiring for Greeter.slice.

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[Copilot]

In the examples table, this description starts with a lowercase “shows”, while the rest of the table consistently uses “Shows …”. Consider capitalizing it (and optionally using “vice versa” without the hyphen) to keep the documentation consistent.

Suggested change

	| [InteropGreeter](./InteropGreeter/) | shows how an IceRPC client can call a service hosted by an [Ice] server, and vice-versa. |
	| [InteropGreeter](./InteropGreeter/) | Shows how an IceRPC client can call a service hosted by an [Ice] server, and vice versa. |